Now to the global alert over ebola, this morning the outbreak in west Africa continues to spread, the world health organization declaring it an international public health emergency. The latest Numbers, more than 1700 infected, more than 960 people dead. And here in the U.S., new worries over whether we're prepared for future viral threats. Here's our chief medical editor Dr. Richard Besser. Reporter: Hollywood has given the catastrophic scenario in movies like contagion, a killer virus raging out of control. In west Africa, it's what experts is happening right now. In Liberia, they struggle to collect body is from terrified people. Trying to keep the healthy from bodily fluids. And while this new outbreak shows the horrors that ebola can show, it's not the only out there. Influenza. It's always surprising us by doing things we're not expecting. Reporter: Just five years ago, swine flu killed more than 150,000 people. 8,000 cases of another virus raised alarms in Asia, sars. And HIV has killed more than 30 million. For ebola, there's no vaccine. Like many viral threats, ebola was likely introduced to humans from animals. Understanding what's out there that could potentially harm us. Reporter: Three years ago in Cameroon, we joined a virus hunter who scours the african rainforest who may be slumbering in the jungle. Other hunters or people preparing animal meat, it can jump to people. They monitor not only the animal blood but blood of local hunters, drops stored on cards. We have collected almost 20,000. Reporter: Whoa. This looks like the kind of lab I might see at the CDC. Absolutely. The hunt for crucial links which have so far prove elusive. There are a lot of things that we don't know about. We never correctly predicted or even predicted at all any pandemic or an emerging infection of an ebola outbreak until it hit the population. Reporter: Worrying signs of the future as experts race to contain the latest outbreak. Our thanks to Dr. Besser. Let's take this on now with our experts. Dr. Frank glover is a medical missionary who worked in Liberia and robin sanders, the former U.S. Ambassador to Congo and Nigeria. Welcome to you both. Dr. Glover, I want to start with you. It seems like the two patients who are now in Atlanta are doing much better, are we out of danger of the virus spreading within the United States? Dr. Glover? Well, no, we aren't out of that danger, this is an international public health emergency that the world health organization just declared on Friday and we're still seeing new cases and new suspected cases popping up in places like Europe, Canada and of course in Nigeria. And back to Africa, you warned congress this week, that unless something is done, this ebola outbreak could spread tens of thousands -- what has to happen in order to prevent that? Well, what has to happen is immediate protective gear must be given to the workers who are on the ground. There's been a large death toll from the nurses and doctors who are trying to treat this disease. The health system has completely collapsed meaning they don't have the capacity to see patients. Every day they're seeing patients, mothers present with dead babies in their wombs, because there's nobody there to do c-section. And they're not getting these protective suits. They're not. Ambassador sanders, you were the ambassador during previous outbreaks, in 2002, 2003, why is this outbreak in western Africa different? Well, the main reason is the population density, in Congo, they're in remote areas. This is population density in Liberia, certainly in Nigeria, the population lives very closely together, so it's very difficult to quarantine, it's easier for the spread of the virus. Because you have such close quarters. Both of you talked about what needs to happen, what will happen and what can happen? It seems like this is desperate. There are a couple of things. One I think the authorities and border patrol authorities across all of the countries that are affected need to communicate better, they need to assure that they're not only quarantine but having Zones of movement. One thing that gets left out of this discussion in terms of how this virus gets into the human population is the food security issue. That's what happened in Liberia. There are food shortages in those same areas. How the virus gets into the population, people are food insecure. They eat what's infected with the disease. Very quickly, to the people of the United States, what would you say in terms of being afraid of this? J I think our health system is much well resourced and we have the capacity and isolation centers all over the country in hospitals. The CDC has made recommendations to the doctors in this country about what precautions to take, people coming from west Africa or infected countries would need to be isolated. To be sure they don't develop sympt symptoms. It seems like they're doing a good job with that, so far, we hope that continues. Thank you very much for joining us.

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